Increase In Bacterial Counts Research Articles

Microbiological and physicochemical changes during ripening in Bulgarian white brined cheese made from raw cow milk

The main microbiological hazards of raw milk cheese are associated with Listeria monocytogenes, Escherichia coli and Staphylococcus aureus. Due to its high nutritional value, cheese is an excellent medium for the growth of these pathogens. This study was aimed to observe microbial dynamics of Bulgarian white brined cheese during cheese production and ripening. Microbiological analysis included determination of Staphylococcus aureus, Listeria spp. and Escherichia coli counts. Some physicochemical parameters, such as total titratable acidity, sodium chloride content, water activity and pH were also examined. Results revealed statistically significant increase in bacterial counts after cheesemaking steps and decrease at the end of the ripening period. Listeria monocytogenes was not detected in any of the cheese samples. Raw milk cheese was of unsatisfactory quality that emphasises the need for applying and maintaining good hygiene practices along the food chain to prevent microbial contamination and growth

Strategies for raw sheep milk storage in smallholdings: Effect of freezing or long-term refrigerated storage on microbial growth

We assessed the effects of freezing and refrigeration over long periods on the microbiological quality of sheep milk. The raw milk was frozen in 1-L plastic bags or 5-L milk buckets and, after 1 mo, thawed at 7 or 25°C. We evaluated these samples immediately after thawing (d 0) and after 1 d of storage at 7°C. Furthermore, we stored fresh raw milk at 7°C for 10 d in the same packages and in a bulk milk cooler at 4°C (adding 10% of fresh raw milk daily). The total bacterial, total psychrotolerant, and proteolytic psychrotolerant counts were evaluated before and after thawing (for previously frozen milk) and daily (for refrigerated milk). The frozen-thawed milks showed no significant increase in bacterial counts immediately after thawing for all samples (<0.7 log cfu/mL), but only the samples packaged in 1-L bags and thawed at 7°C remained microbiologically adequate after 1 d of storage. Findings of the refrigerated samples were modeled using a modified Gompertz equation, obtaining a lag phase of around 0.5 (5-L bucket), 2.6 (1-L bag), and 7.0 (bulk milk cooler) d for total bacterial and total psychrotolerant counts. Maximum growth rates (µmax) were 1.0 and 1.0 (5-L bucket), 1.2 and 1.3 (1-L bag) and 3.0 and 1.5 (bulk milk cooler) ln(cfu/mL) per day for total bacteria and total psychrotolerant counts, respectively. Compared with total bacteria and total psychrotolerant bacteria, psychrotolerant proteolytic bacteria grew slowly, reaching unacceptable counts only after 9 to 10 d of storage. The studied methods are interesting alternatives for preserving raw sheep milk on smallholdings.

Extending the 30-minute rule for red cell units - investigation of the bacterial risk of 60-minute exposures to ambient temperature.

In the UK, a significant proportion of red cell units is discarded due to the 30-min rule governing out of temperature control. Studies have shown that repeated warming to ambient temperature has little impact on red cell quality or bacterial growth. We aimed to validate extension of the rule to 60 minutes by investigation of repeated same, and different, day exposures on bacterial growth. Red cell units were seeded individually at 100-1000 cfu/ml with Yersinia enterocolitica, Serratia liquefaciens, Pseudomonas putida, Staphylococcus epidermidis, Enterobacter cloacae and Bacillus cereus. Test units were exposed to 30°C for 30 or 60 min on a single occasion at days 15, 17 and 21, or thrice on day 15 of a 35-day storage period. A 10-fold increase in bacterial counts in tests versus controls maintained in cold storage was considered indicative of significant bacterial proliferation. Exposure of units to 30°C for up to 60 min had no substantial impact on the growth of bacteria and all mesophiles declined steadily in tests and controls. Only P. putida showed a near significant elevation in count on exposure for 60 min at day 35. Extension of the out of temperature rule for red cells to 60 min will potentially not compromise patient safety, although exposures to ambient temperatures should be minimized. Units returned to storage must not be reissued for at least 6 hours and not be exposed to ambient temperatures on more than three occasions.

Detection of fecal bacteria and antibiotic resistance genes in drinking water collected from three First Nations communities in Manitoba, Canada.

This study analyzed the microbiological quality of drinking and source water from three First Nations communities in Manitoba, Canada that vary with respect to the source, storage and distribution of drinking water. Community A relies on an aquifer and Community B on a lake as source water to their water treatment plants. Community C does not have a water treatment plant and uses well water. Quantification of free residual chlorine and fecal bacterial (E. coli and coliforms), as well as detection of antibiotic resistance genes (sul, ampC, tet(A), mecA, vanA, blaSHV, blaTEM, blaCTX-M, blaOXA-1, blaCYM-2, blaKPC, blaOXA-48, blaNDM, blaVIM, blaGES and blaIMP) was carried out. While water treatment plants were found to be working properly, as post-treatment water did not contain E. coli or coliforms, once water entered the distribution system, a decline in the chlorine concentration with a concomitant increase in bacterial counts was observed. In particular, water samples from cisterns not only contained high number of E. coli and coliforms, but were also found to contain antibiotic resistance genes. This work shows that proper maintenance of the distribution and storage systems in First Nations communities is essential in order to provide access to clean and safe drinking water.

Relationship between acetaldehyde concentration in mouth air and characteristics of microbiota of tongue dorsum in Japanese healthy adults: a cross-sectional study.

Acetaldehyde, associated with consumption of alcoholic beverages, is known to be a carcinogen and to be related to the tongue dorsum. Objective The aim of this study was to investigate the relationship between acetaldehyde concentration in mouth air and bacterial characteristics on the tongue dorsum.Methodology Thirty-nine healthy volunteers participated in the study. Acetaldehyde concentrations in mouth air were evaluated by a high-sensitivity semiconductor gas sensor. A 16S rRNA gene sequencing technique was used to compare microbiomes between two groups, focusing on the six samples with the highest acetaldehyde concentrations (HG) and the six samples with lowest acetaldehyde concentrations (LG).Results Acetaldehyde concentration increased in correlation with the increase in bacterial count (p=0.048). The number of species observed in the oral microbiome of the HG was higher than that in the oral microbiome of the LG (p=0.011). The relative abundances of Gemella sanguinis, Veillonella parvula and Neisseria flavescens in the oral microbiome of the HG were higher than those in the oral microbiome of the LG (p<0.05).Conclusion Acetaldehyde concentration in mouth air was associated with bacterial count, diversity of microbiome, and relative abundance of G. sanguinis, V. parvula, and N. flavescens.

An ex vivo porcine spleen perfusion as a model of bacterial sepsis.

An ex vivo, porcine spleen perfusion model was established to study the early events occurring in the spleen prior to the onset of bacterial sepsis, using organs retrieved from animals slaughtered for food production. Porcine spleens were harvested from adult pigs and connected to a normothermic extracorporeal perfusion circuit. A constant perfusion of heparinized blood was performed for 6 hours. After injection of Streptococcus pneumoniae to the circuit serial samples of both blood and spleen biopsies were collected and analysed. Functionality of the perfused organs was assessed by monitoring the blood-gas parameters, flow rate and filtering capability of the organ. Interestingly, we observed full clearance of bacteria from the blood and an increase in bacterial counts in the spleen. Classical histology and immunohistochemistry on biopsies also confirmed no major damages in the organ architecture and changes in the immune cell distribution, other than the presence of clusters of pneumococci. A time-course study confirmed that each focus of infection derived from the replication of single pneumococcal cells within splenic macrophages. The model proposed - in line with the 3Rs principles - has utility in the replacement of experimental animals in infection research. Murine models are prevalently used to study pneumococcal infections, but are often not predictive for humans due to substantial differences in the immune systems of the two species. This model is designed to overcome these limitations, since porcine immunology and splenic architecture in particular, closely resemble those of humans.

The influence of product acidity and beta-glucans isolated from various sources on the mineral composition and the mechanical and microstructural properties of the femur in growing Wistar rats

The aim of this study was to determine the influence of a standard diet enriched with yoghurt (acidified milk) and milk gel (non-acidified milk) and three structurally different beta-glucans (isolated from oats, bacteria and fungi) on the mineral composition and the mechanical and microstructural properties of the femur in growing rats.Feed intake and the feed conversion ratio were influenced by product acidity and the applied beta-glucan. A significant increase in bacterial counts was noted only in the animals fed fungal glucan. Dietary supplementation with beta-glucans significantly decreased the acidity of intestinal contents. The calcium content of bones was determined mainly by the acidity of milk gel than by the type of beta-glucans. The Ca:P ratio in the femurs of rats fed yoghurt was higher than in the animals fed milk gel. Higher failure load was noted in rats fed yoghurt with beta-glucans. Trabecular thickness was highest in rats fed yoghurt with oat beta-glucan and lowest in rats fed milk gel with fungal beta-glucan.

EVALUATION OF GARCINIA CAMBOGIA PLANT EXTRACTS ANTIFUNGAL, ANTIBACTERIAL AND ANTIOXIDANT

In the present investigation, the antioxidant, antifungal and antibacterial activities of Garcinia cambogia plant extracts were studied. Hot and cold of aqueous extracts of 5, 7.5 and10% (w/v) concentrations were used as a natural preservative beverage. These prepared extracts were used for evaluation of their antifungal (against Fusarium moniliforme and Aspergillus flavus) and antibacterial properties (against gram-negative bacterial strains, Escherichia coli and gram-positive bacterial strains, Bacillus cereus). Such materials have a high content of polyphenol compounds such as pyrogallol, catechin, catechol, epicatechein, chlorogenic and salycilic acid in addition to flavonoides and isoflavonoides compounds. Garcinia cambogia contains considerable amounts of water and fat soluble vitamins. Sensory evaluation of Guava nectar supplemented with Garcinia cambogia extracts (7.5 and10% w/v) as a natural preservative, showed no significant difference in taste, colour, texture, flavour and appearance compared with control. The data showed no microbial spoilage in guava nectar supplemented with different Garcinia cambogia (cold and hot) extract concentrations and control at zero time. After one and two weeks of storage nectar in the refrigerator showed an increase in total bacterial counts in the control, meanwhile, guava nectar containing Garcinia cambogia extracts (7.5% and 10%) cold and hot showed a slight increase in bacterial count. It could be concluded that Garcinia cambogia plants has high antioxidant, antibacterial, antifungal activity properties which have some beneficial effects on health and can be used as natural preservative substances in food and beverages.

Influence of preservation methods on the quality of colostrum sourced from New Zealand dairy farms

AIMS: To assess the effect of two temperatures (ambient temperature and 4°C), three preservation methods (no preservative, yoghurt and potassium sorbate), and two periods of storage (3 and 7 days) on Brix and total bacterial and coliform counts of colostrum collected from New Zealand dairy farms.METHODS: One litre of colostrum destined to be fed to newborn calves was collected from 55 New Zealand dairy farms in the spring of 2015. Six aliquots of 150 mL were obtained from each colostrum sample, with two aliquots left untreated, two treated with potassium sorbate and two with yoghurt, and one of each pair of aliquots stored at ambient temperature and the other at 4°C. All samples were tested for Brix, total bacterial counts and coliform counts before treatment (Day 0), and after 3 and 7 days of storage. The effect of preservation method and storage temperature on the change in Brix, bacterial and coliform counts after 3 or 7 days of storage was analysed using multivariable random effects models.RESULTS: For all outcome variables there was a temperature by preservation interaction. For aliquots preserved with potassium sorbate, changes in Brix and bacterial counts did not differ between aliquots stored at ambient temperature or 4°C, but for aliquots preserved with yoghurt or no preservative the decrease in Brix and increase in bacterial counts was greater for aliquots stored at ambient temperature than 4°C (p<0.001). For aliquots preserved with potassium sorbate, coliform counts decreased at both temperatures, but for aliquots preserved with yoghurt or no preservative coliform counts increased for aliquots stored at 4°C, but generally decreased at ambient temperatures (p<0.001). There was also an interaction between duration of storage and temperature for bacterial counts (p<0.001). The difference in the increase in bacterial counts between aliquots stored at 4°C and ambient temperature after 3 days was greater than between aliquots stored at 4°C and ambient temperature after 7 days.CONCLUSIONS AND CLINICAL RELEVANCE: Use of potassium sorbate to preserve colostrum for 3 or 7 days resulted in little or no reduction in Brix and a lower increase in total bacterial counts than colostrum stored without preservative or with yoghurt added. Colostrum quality was not affected by storage temperature for samples preserved with potassium sorbate, but storage at 4°C resulted in better quality colostrum than storage at ambient temperatures for colostrum with no preservative or yoghurt added.

CD4+ T cell control of Salmonella infection and persistence is dependent on different macrophage subsets

Abstract The control of the persistent phagosomal pathogen, Salmonella enterica (Se), by the adaptive immune system is dependent on pathogen-specific CD4+ T-helper 1 (Th1) cells. To explore the hypothesis that Se uses a specific cellular niche to evade Th1 cells in order to persist, we generated a strain of Se that expresses a chromosomally-encoded dTomato protein that displays bright and stable fluorescence in vivo. Following oral infection in 129sv/J mice we found dTomato+ cells in macrophage (MΦ), monocyte, and neutrophil populations. Depletion of neutrophils during infection had no effect on bacterial burden or survival. In contrast, depletion of monocytes and MΦ in CCR2 or LysM-Cre CD115 stop-flox diphtheria toxin (DT) receptor transgenic mice increased bacterial counts and death 6–8 days after DT treatment, indicating an important role for these cells in maintaining Se persistence. Depletion of CD4+ T cells led to increases in bacterial counts and an altered infected cell profile compared to control animals. The frequency of infected CD11bHi MerTKInt infiltrating MΦ was increased, while infected CD11bIntMerTKHi tissue resident MΦ remained relatively constant, suggesting that Th1 cells interact preferentially with infiltrating MΦ. Infected tissue resident MΦ expressed less MHCII, CD86 and more PD-L1 and PD-L2 than uninfected counterparts, and a reciprocal expression pattern was observed on infected infiltrating MΦ. These data suggest that Th1 cells promote killing of intracellular Se in infiltrating MΦ and either ignore or are inhibited by infected tissue resident MΦ providing a reservoir where Se can persist for the lifetime of the infected animal.

Protective role of Lactobacillus fermentum R6 against Clostridium perfringens in vitro and in chicken breast meat under temperature abuse conditions

Abstract Six bacterial species were evaluated to determine their inhibitory effects on Clostridium perfringens in vitro (brain heart infusion broth) and in situ (chicken breast meat) under temperature abuse conditions (4 ± 1 °C for 12 h, followed by 7 h at 28 ± 1 °C and then 4 ± 1 °C for 53 h). During abusive storage, rapid growth of C. perfringens from vegetative cell and spore inocula was observed, exhibiting a 2.68–3.37 log CFU/mL (or g) increase in bacterial counts. In the presence of Pediococcus pentosaceus P1 or Lactobacillus fermentum R6, the counts of C. perfringens remained unchanged in the samples containing vegetative cells at the end of storage (P 1.9 log CFU/mL (or g) compared to those of the control (P 0.05), and the inhibitory effect against C. perfringens was ascribed to non-acid antimicrobial substances. These results indicate a potential solution for bio-protecting chicken meat from C. perfringens growth. Industrial relevance Clostridium perfringens is a common pathogen that contaminates meat and meat products, but the organism cannot multiply under cold chain conditions at 4 °C. However, it was reported that temperature abuses commonly occurred during the transportation, storage or retail display of the food chill chain. During the abusive storage, C. perfringens could grow rapidly, which may lead to food poisoning. It is a serious problem for food safety. In this study, Lactobacillus fermentum R6 was found to show effective inhibition on both the growth of C. perfringens vegetative cells and the germination and outgrowth of its spores in chicken meat (P 0.05). The results reveal a potential technology for bio-protecting chicken meat from C. perfringens growth.

Forced-Air Warmers and Surgical Site Infections in Patients Undergoing Knee or Hip Arthroplasty.

The majority of the evidence indicates preventing inadvertent perioperative hypothermia reduces the incidence of many perioperative complications. Among the results of inadvertent perioperative hypothermia are increased bleeding, myocardial events, impaired wound healing, and diminished renal function. Most researchers agree there is an increased incidence of surgical site infections in patients who experience inadvertent perioperative hypothermia. Forced-air warming is effective in preventing inadvertent perioperative hypothermia. Paradoxically, forced-air warmers have been implicated in causing surgical site infections in patients undergoing total knee or hip arthroplasty. The results of investigations suggest these devices harbor pathogens and cause unwanted airflow disturbances. However, no significant increases in bacterial counts were found when forced-air warmers were used according to the manufacturer's directions. The results of one study suggested the incidence of surgical site infections in patients undergoing total joint arthroplasty was increased when using a forced-air warmer. However these researchers did not control for other factors affecting the incidence of surgical site infections in these patients. Current evidence does not support forced-air warmers causing surgical site infections in patients undergoing total knee or hip arthroplasty. Clinicians must use and maintain these devices as per the manufacturer's directions. They may consider using alternative warming methods. Well-conducted studies are needed to help determine the role of forced-air warmers in causing infections in these patients.

Effect of Camphylobacter rectus on Serum Iron and Transferrin- In-Vivo Findings.

Periodontopathogens require iron constituents for their growth and metabolism in subgingival crevice. In this study, C.rectus was detected and quantified by using 16s rDNA based PCR in chronic periodontitis and compared with the levels of serum iron, total iron binding capacity and transferrin in chronic periodontitis and healthy sites. One hundred twenty subjects divided into chronic periodontitis and healthy controls. Deep subgingival plaque was collected and genomic DNA was extracted from each sample analysed for C.rectus using 16s rRNA based PCR analysis. Blood samples were collected from both groups for estimation of serum iron, serum total iron binding capacity and serum transferrin levels. The quantified bacterial count was compared with blood samples. C. rectus was detected in both groups. There was significant increase in bacterial count in chronic periodontitis (p<0.05). Serum iron level was significantly raised in healthy group. TIBC and transferrin levels were elevated in periodontitis. Although these differences were non-significant. Regression analysis showed significant linear relationship between C.rectus counts and decreasing iron levels and consequently increasing serum transferrin and TIBC (p<0.05). The preliminary in vivo findings suggests C.rectus requires iron as a significant source of nutrition for its survival and growth form its hosts in deeper subgingival sites.

Evaluation of antimicrobial efficacy of Aloe vera and Meswak containing dentifrices with fluoridated dentifrice: An in vivo study.

Aim:To comparatively evaluate the antimicrobial efficacy of fluoridated and herbal dentifrices.Materials and Methods:Sixty students in the age group 6–12 years with DMF/def score 0 were selected from an orphanage center. The participants were divided into four groups. In group A, no dentifrice was used; in group B, fluoride containing dentifrice was used; group C subjects used Aloe vera containing dentifrice; and in group D, Meswak containing dentifrice was used. The salivary samples were collected at the washout period of 2 days, 15 days, and 30 days and cultured on Mitis Salivarius Agar for determining Streptococcus mutans count. Results obtained were statistically analyzed using Student's t-test.Results:There was an increase in bacterial count in group A where no dentifrices were used, while the bacterial count steadily decreased in groups B, C, and D by 83.7%, 80.94%, and 83.5%, respectively.Conclusion:Herbal dentifrices containing A. vera and Meswak can be safely recommended as an alternative to fluoridated dentifrices in terms of antimicrobial efficacy.

Effects of dietary polysaccharides from the submerged fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. on performance, gut microflora, and cholesterol metabolism in broiler chickens

The present study was conducted to investigate the effects of polysaccharides from the submerged fermentation concentrate of Hericium caput-medusae (Bull.:Fr.) Pers. (HFCP) on growth performance, gut microflora, and cholesterol metabolism in broiler chickens. A total of 480 one-day-old Arbor Acres male broilers were randomly assigned to 4 treatment groups with 6 pens per treatment and 20 broilers per pen. Diets containing 4 concentrations of HFCP (0, 1, 3, and 5g/kg) were fed to the broiler chickens. The experimental diets were fed in 2 phases, starter period (d 0 to 21) and finisher period (d 21 to 42). The results indicated that the average daily gain and the average daily feed intake increased (P<0.01) both linearly and quadratically when the HFCP levels increased. However, there was no difference in feed conversion observed among different treatment groups in each period. The serum total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels decreased (P<0.001) linearly and quadratically, while the high-density lipoprotein cholesterol level increased (linear and quadratic, P<0.001) with increasing dietary HFCP levels. The caecum Escherichia coli count and pH decreased (P<0.001) linearly and quadratically, while the caecum lactobacilli count, bifidobacteria count, and propionic acid concentration increased (linear and quadratic, P<0.01) as the HFCP levels increased. On d 21 and 42, the cholesterol content in liver, thigh, and breast muscle decreased (P<0.01) linearly and quadratically, while the bile acid excretion increased (linear and quadratic, P<0.001) with increasing dietary HFCP levels. Different doses of HFCP supplementation in broiler diets had no effect on cholesterol content in excreta. In conclusion, dietary supplementation with HFCP may lead to the production of low-cholesterol broiler meat demanded by health conscious consumers, and its effect might be due to the increase in bacterial count and short chain fatty acids production in the large intestine, and the accelerated rate of catabolism of cholesterol to bile acids by HFCP.

Enrichment effect of dietary fiber on certain qualitiy attributes of fat reduced pork patties: physico chemical and microbiological qualities

Pork patties were prepared by incorporating wheat bran (WB) and oat bran (OB) as dietary fiber source at three different levels i.e. WB 1 and OB 1 @ 2%, WB 2 and OB 2 @ 3% and WB 3 and OB 3 @ 4%, besides a control group (C T ) with no added dietary fiber. The pH values of pork patties did not differ significantly between the C T and treated products. The a w values differed significantly (P < 0.01) between the C T and treated products during the storage period from 1 st to 15 th day. The TVPBC ( log cfu/g) recorded were higher (P < 0.01 ) in C T as compared to the treated products on day-1 and also on subsequent storage days. Amongst the treated patties, WB 3 and OB 3 recorded lowest and WB 1 and OB 1 had the highest TVPBC which, however, was lower than the C T . All the treated products recorded a progressive increase in bacterial counts along with the increased duration of storage. The counts for colititre ( MPN) revealed their absence irrespective of the storage days and both in the C T and treated products.

The Sensitivity of PCR to the Number of Lactococcus garvieae in Different Concentrations of NaCl: FTA Technique

The major objective of this study is to investigate the sensitivity of PCR to the number of Lactococcus garvieae (L. garvieae) in sterilized milk containing different concentrations of NaCl using FTA technique for genomic DNA extraction. This technique is a simple, rapid, precise and highly sensitive even to low count of bacterial cells in samples. The study used M17 medium to determine the number of bacterial cells, thereafter, FTA method was used for genomic DNA extraction. The results using M17 medium, indicated that the L. garvieae increased in all concentrations of NaCl during an incubation period of 24 hours, on the other hand, pH value decreased. However, the increase in bacterial count was statistically significant only on 0, 2% and 4% of NaCl concentrations. In conjunction with this, the PCR showed sensitivity to both low and high numbers of bacterial cells in the samples. Increasing bacterial numbers led to an increase in the amount of DNA extracted via FTA cards and therefore, the intensity and clarity of bands of PCR reaction was also increased. This is the first study that uses FTA technique for DNA extraction in dairy products. Using FTA cards and subjecting to PCR in quantifying the bacterial growth is a very important issue because of its direct application in the field of milk, agricultural and animal products research and development.

Evaluation of lima bean flour fermented with Lactobacillus sp. as a probiotic food

The probiotic potential of lima bean flour fermented with Lactobacillus sp. in vitro and in vivo was studied. 3 species of Lactobacillus including Lactobacillus fermentum,Lactobacillus plantarum and Lactobacillus cellebiosus were isolated from traditionally prepared ‘ogi’ made from white and yellow maize (Zea mays) and from red guinea corn (Sorghum bicolor), after which they were screened for their growth and survival in Lima bean flour. Among all the species, L. plantarum showed appreciable growth (9.3 × 106 cfu/ml) after 72 h fermentation at 37°C. On storing the fermented products for 14 days at 24 ± 2°C, no marked change in the viable count of this species was observed. In contrast, the number of other species, that is, L. fermentum and L. cellebiosusreduced. There was marked increase in bacterial counts of all the products after storage at room temperature (24 ± 2°C) for 14 days compared to those stored at refrigeration temperature (4 ± 2°C). The physicochemical analysis of the fermented samples showed increase in total titratable acidity (TTA) and temperature with a gradual reduction in pH. There was an increase in protein content and decrease in carbohydrate, ash and moisture contents in the fermented sample compared with the unfermented sample. Under different pH ranges, L. plantarum also showed appreciable growth and survival at pH 2 to 3. Supplementing the diet of albino rats infected with Escherichia coli with the fermented product increased significantly the number of Lactobacilli, compared to the control and at the same time, the number of E. coli and other feacal enterobacteria decreased significantly. This study revealed that Lima bean flour fermented with L. plantarum could be used as an excellent probiotic food. Key words: Lactobacillus species, lima beans, fermentation, probiotics and gastrointestinal tolerance.

Transverse Chemotactic Migration of Bacteria from High to Low Permeability Regions in a Dual Permeability Microfluidic Device

Low permeability regions such as clay lenses are difficult to remediate using conventional treatment methods. Bacterial chemotaxis (directed migration toward a contaminant source) may be helpful in enhancing bioremediation of such contaminated sites. This study experimentally simulates a two-dimensional dual-permeability groundwater contamination scenario using a microfluidic device (MFD) and evaluates transverse chemotactic migration of bacteria from high to low permeability regions under various flow velocities. Chemotaxis of Escherichia coli (E. coli) HCB33 to the chemoattractant dl-aspartic acid was quantified in terms of change in total bacterial counts in pore throats in low permeability regions containing attractant. An increase in total bacterial counts, ranging from 1.09 to 1.74 times, was observed in low permeability regions in experiments under chemotactic conditions. Experiments with no attractant showed no increase in total bacterial counts in low permeability regions. A large increase in bacterial counts in the pore throats just outside the low permeability region was also observed in chemotaxis experiments. The bacterial chemotactic response was observed to decrease linearly with increase in flow velocity, with no observed response at the highest flow velocity (Darcy velocity = 0.22 mm/s), where chemotaxis was offset by advective flow.

Effect of alginate chemical disinfection on bacterial count over gypsum cast

PURPOSETo evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast.MATERIALS AND METHODSFour alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 213). Gypsum cast (type III) were made from all the impression. Impressions and gypsum cast were swabbed in mid palatal region for bacterial culture. Bacterial colony counting done after 3 days of incubation at 37℃ in blood agar media. The data obtained was analyzed by one way ANOVA test at a significant difference level of 0.05.RESULTSGroup I and Group II showed significantly more bacteria compared to Group III and Group IV. Bacterial colonies on the alginate impression and gypsum cast in group disinfected with Sodium hypochlorite (1 : 10) were 0.18, 0.82 respectively compared to group treated with iodophor (1 : 213). There was an increase in bacterial count on dental cast compared to source alginate impressions.CONCLUSIONSodium hypochlorite (1 : 10) was found to be better disinfectant for alginate impression. There was an indication of increase in number of bacteria from alginate impression to making of dental cast. Additional gypsum cast disinfectant procedures need to be encouraged to completely eliminate cross infection to dental laboratory.